Microtia: ear reconstruction using tissue expander and autogenous costal cartilage

Ear reconstruction is one of the most challenging surgeries faced by the reconstructive surgeon. Currently, the use of autogenous costal cartilage is still best practice for microtia reconstruction. However, the relative deficiency of thin skin for coverage of the cartilage framework remains a limiting factor. Since 1994, we have used tissue expander in the mastoid area and innovated a technique to fabricate cartilage framework. All these innovations may solve the deficiency of the skin and improve cartilaginous framework definition. In conclusion, tissue expander offers a non-hairbearing, thin, well-vascularised skin to envelope an erect, contour-accentuated framework. Most patients with microtia are satisfied with their ear reconstruction.

Genetic variation in a human odorant receptor alters odour perception

Human olfactory perception differs enormously between individuals, with large reported perceptual variations in the intensity and pleasantness of a given odour. For instance, androstenone (5alpha-androst-16-en-3-one), an odorous steroid derived from testosterone, is variously perceived by different individuals as offensive ("sweaty, urinous"), pleasant ("sweet, floral") or odourless. Similar variation in odour perception has been observed for several other odours. The mechanistic basis of variation in odour perception between individuals is unknown. We investigated whether genetic variation in human odorant receptor genes accounts in part for variation in odour perception between individuals. Here we show that a human odorant receptor, OR7D4, is selectively activated in vitro by androstenone and the related odorous steroid androstadienone (androsta-4,16-dien-3-one) and does not respond to a panel of 64 other odours and two solvents. A common variant of this receptor (OR7D4 WM) contains two non-synonymous single nucleotide polymorphisms (SNPs), resulting in two amino acid substitutions (R88W, T133M; hence 'RT') that severely impair function in vitro. Human subjects with RT/WM or WM/WM genotypes as a group were less sensitive to androstenone and androstadienone and found both odours less unpleasant than the RT/RT group. Genotypic variation in OR7D4 accounts for a significant proportion of the valence (pleasantness or unpleasantness) and intensity variance in perception of these steroidal odours. Our results demonstrate the first link between the function of a human odorant receptor in vitro and odour perception.

Synergism of Accessory Factors in Functional Expression of Mammalian Odorant Receptors

The discovery of odorant receptors led to endeavors in matching them with their cognate ligands. Although it has been challenging to functionally express odorant receptors in heterologous cells, previous studies have linked efficient odorant receptor expression with N-terminal modifications and accessory proteins, including the receptor-transporting proteins (RTPs) and Ric8b. Here we have shown that a shorter form of RTP1, RTP1S, supports robust cell-surface and functional expression of representative odorant receptors. Using a combination of accessory proteins, including RTP1S, Ric8b, and G(alphaolf), a diverse set of untagged odorant receptors were successfully expressed heterologously due to the synergistic effects among the various accessory proteins. Furthermore, the addition of an N-terminal rhodopsin tag to the odorant receptors, along with the same set of accessory proteins, exhibits an additional level of synergism, inducing enhanced odorant receptor responses to odorants and thus defining a more efficient heterologous expression system. We then showed that the presence or absence of different N-terminal tags has little effect on the ligand specificity of odorant receptors, although the amount of receptor expressed can play a role in the ligand response profile. The accuracy of the odorant receptor heterologous expression system involving tagged odorant receptors and various accessory proteins promises success in high throughput de-orphaning of mammalian odorant receptors.

Transient receptor potential family members PKD1L3 and PKD2L1 form a candidate sour taste receptor

Animals use their gustatory systems to evaluate the nutritious value, toxicity, sodium content, and acidity of food. Although characterization of molecular identities that receive taste chemicals is essential, molecular receptors underlying sour taste sensation remain unclear. Here, we show that two transient receptor potential (TRP) channel members, PKD1L3 and PKD2L1, are coexpressed in a subset of taste receptor cells in specific taste areas. Cells expressing these molecules are distinct from taste cells having receptors for bitter, sweet, or umami tastants. The PKD2L1 proteins are accumulated at the taste pore region, where taste chemicals are detected. PKD1L3 and PKD2L1 proteins can interact with each other, and coexpression of the PKD1L3 and PKD2L1 is necessary for their functional cell surface expression. Finally, PKD1L3 and PKD2L1 are activated by various acids when coexpressed in heterologous cells but not by other classes of tastants. These results suggest that PKD1L3 and PKD2L1 heteromers may function as sour taste receptors.

Heme oxygenase-1 protects brain from acute excitotoxicity

Heme oxygenase is a rate-limiting enzyme that degrades heme, a pro-oxidant, into carbon monoxide, iron, and bilirubin. Heme oxygenase has two active isoforms: heme oxygenase-1 and heme oxygenase-2. Heme oxygenase-1 can be induced by various insults. Several investigators have postulated that it has cytoprotective activities, although its role in the nervous system is not fully understood, especially considering that normally heme oxygenase-2 accounts for the vast majority of heme oxygenase activity in the brain. Here, the basal effect of heme oxygenase-1 was investigated in acute glutamatergic excitotoxicity to test the hypothesis that N-methyl-D-aspartate-induced acute toxicity in brain is attenuated by heme oxygenase-1. N-methyl-D-aspartate was unilaterally injected into the striatum of wildtype and heme oxygenase-1 knockout mice. After 48 h, brains were harvested, sectioned, and stained with Cresyl Violet to measure the lesion size. Lesion volume was significantly (P<0.05) greater in brains of heme oxygenase-1 knockout mice (15.2+/-3.1 mm(3); n=10) than in those of wildtype mice (6.2+/-1.5 mm(3); n=11). In addition, Western blot analysis indicated no detectable differences between wildtype and heme oxygenase-1 knockout mouse brains in the levels of the glutamate or N-methyl-D-aspartate receptors studied. To test whether heme oxygenase-1 could specifically protect neurons, mouse primary neuronal cell cultures of wildtype and heme oxygenase-1 knockout mice were treated with or without N-methyl-D-aspartate. Cell viability of the heme oxygenase-1 knockout neurons was significantly less than that of wildtype neurons at each of the N-methyl-D-aspartate concentrations tested (12.8+/-1.3%, 16.0+/-1.4%, and 18.4+/-1.8% at 30, 100, and 300 microM N-methyl-D-aspartate, respectively). These results indicate that heme oxygenase-1 provides neuroprotection against acute excitotoxicity and suggest that potential intervention that can increase heme oxygenase-1 activity within the brain should be considered as a therapeutic target in acute and potentially chronic neurological disorders.

Detection of mutA genes in transmitted strains and nontransmitted strains of mutans streptococci

Our aim was to determine whether an isolate carrying one of the mutA genes was related to its ability to be transmitted from mother to her child. First, 200 mutans streptococci isolates were genotyped by arbitrarily primed polymerase chain reaction (AP-PCR) to demonstrate transmission between 20 mother-child pairs and to detect the transmitted and nontransmitted strains. Then the mutacin structural genes mutA encoding mutacin types I, II, and III were screened by PCR. The results showed that all strains found to carry the mutAI gene were nontransmitted strains; PCR screening primers mutAII and mutAIII did not yield amplicons in any of the strains tested. Our data suggest that an isolate carrying the mutAI gene is related to reduced transmission. The low frequency of detection of mutAII, and mutAIII suggests that there is a high heterogeneity in the genetic determinants needed for the production of mutacin-like substances.

Positron emission tomography imaging in evaluation of cancer patients

Positron emission tomography (PET) is a diagnostic imaging technique that has progressed rapidly from being a research technique in laboratories to a routine clinical imaging modality. The most widely used radiotracer in PET is Fluorine18-fluorodeoxyglucose (F18-FDG), which is an analogue of glucose. The FDG uptake in cells is directly proportional to glucose metabolism of cells. Since glucose metabolism is increased many fold in malignant tumors PET has a high sensitivity and a high negative predictive value. PET with FDG is now the standard of care in initial staging, monitoring the response to the therapy, and management of lung cancer, colonic cancer, lymphoma, melanoma, esophageal cancer, head and neck cancer and breast cancer. Other indications of PET like bone tumor, ovarian cancer and cancer of unknown primary (CUP) has also been discussed in brief. The aim of this review article is to review the clinical applications of PET in various malignancies and only limited number of important studies will be discussed for this effort.

Applications of fluorodeoxyglucose positron emission tomography in the diagnosis of infection

The purpose of this study was to assess the accuracy of fluorodeoxyglucose positron emission tomography (FDG PET) in diagnosing infection in a large population of patients and in a variety of clinical circumstances where the performance of conventional imaging modalities has been questioned. We retrospectively analysed 167 FDG PET scans obtained to evaluate 175 anatomical sites for the presence of infection. The major indications for the scans were (1) complicated orthopaedic hardware (n=97), (2) chronic osteomyelitis (n=56), and (3) other (n=14: six fever of unknown origin, three vascular grafts, and five soft tissue). We assessed the overall diagnostic accuracy of FDG PET for each of these indications. In addition, we further analysed this modality's effectiveness by grouping the scans into specific clinical situations. A final diagnosis was made on the basis of surgical pathology and clinical follow-up for a minimum of 6 months. The overall accuracy of FDG PET in evaluating orthopaedic hardware was 96.2% for hip prosthesis, 81% for knee prosthesis, and 100% in 15 patients with other orthopaedic devices. Among the patients in our sample suspected of having chronic osteomyelitis, the accuracy was 91.2%. FDG PET was inaccurate in three cases of fever of unknown origin and accurate in all vascular graft and soft tissue infections. In 49 patients with a clinically apparent soft-tissue infection, FDG PET was able to detect or exclude underlying osteomyelitis with an accuracy of 92.3%. Among the 23 patients who had recent orthopaedic procedures, FDG PET imaging was accurate in 87% of cases. It is concluded that FDG PET is a highly effective imaging modality in the assessment of patients with suspected infection.

Sentinel lymph node biopsy in the management of breast cancer

Sentinel node localization is the second most important development in this century after conservative lumpectomy for the treatment of early breast cancer. The sentinel node mapping is a new multidisciplinary approach for staging of axilla in an accurate and less morbid way as compared to axillary node dissection. Sentinel lymph node biopsy in patients with breast cancer has been adopted rapidly into clinical practice. The accuracy of sentinel lymph node biopsy is more than 95%, when performed meticulously (by an experienced multidisciplinary team) with proper patient selection. Sentinel lymph node biopsy is most widely used for both palpable and non-palpable T1 and T2 tumors. Recent studies show application of sentinel lymph node technique in patients with locally advanced breast cancer and after neoadjuvant chemotherapy. Therefore, sentinel lymph node biopsy technique has application in developing countries and other countries where screening for breast cancer is not common and most patients present relatively in advanced stage of the disease. Several aspects of the sentinel lymph node biopsy including technique, case selection, pathologic analysis and accuracy with supportive important studies published in the literature will be discussed in this review.

Effect of fluoride pretreatment on the solubility of synthetic carbonated apatite

The purpose of this research was to address the following question: How is the solubility of fluoride-pretreated carbonated apatite (CAP) in aqueous acidic media related to the equilibrium solution fluoride and/or the CAP adsorbed fluoride levels? A CAP sample prepared by a precipitation method at 70 degrees C containing approximately 6% carbonate was fluoride-treated (F adsorption from neutral aqueous solutions) to yield a approximately 1000 ppm F CAP and a approximately 3300 ppm F CAP. Metastable equilibrium solubility distributions were determined in acetate buffers at pH 5.0. Solution fluoride, calcium, phosphate, and pH were determined from the equilibrated solutions. The equilibrium solution fluoride levels were extremely low, e.g., as low as approximately 0.10 ppb to approximately 0.30 ppb at 50% dissolved for the two CAP preparations. The approximately 3300 ppm F CAP yielded a lower solubility than the approximately 1000 ppm F CAP (shift in the mean pKHAP value of 1.5-2 units). This can be attributed to the lower solution F(-) for the sample containing approximately 1000 ppm fluoride compared with the approximately 3300 ppm fluoride-containing CAP. These important findings suggest that a fluoride treatment simply may provide an adsorption fluoride depot for subsequent release, providing a solution fluoride effect upon the CAP solubility and not necessarily any intrinsic alteration of the mineral solubility.

The importance of the location of fluorodeoxyglucose uptake in periprosthetic infection in painful hip prostheses

Ten per cent of patients with hip replacement will eventually complain of significant pain after surgery, often requiring a revision arthroplasty. The majority of these patients experience aseptic loosening rather than infection. Despite significant advances made in diagnostic imaging, distinguishing infection from aseptic loosening remains a significant challenge. Imaging using fluorodeoxyglucose (FDG) positron emission tomography (PET) has been reported to have excellent sensitivity in detecting infections associated with hip prostheses. However, in some studies, a high rate of false positive results has been reported, especially when increased tracer uptake adjacent to the prosthesis (which is not surrounded by bone) is used as the sole criterion for diagnosing infection. The objective of this investigation was to determine the optimal criteria for diagnosing periprosthetic infection, thereby avoiding false positive results in this setting. A total of 41 total hip arthroplasties from 32 patients and for whom complete clinical follow-up was available were included in this analysis. The location and intensity of FDG uptake were determined for each scan. Final diagnosis was made by microbiology, histopathology, surgical findings and clinical follow-up. Patients who did not undergo surgery were followed up to at least 9 months. Twelve patients were proven eventually to have periprosthetic infection. Images from 11 of these patients displayed increased tracer uptake along the interface between bone and prosthesis. The intensity of the increased tracer uptake varied from mild to moderate, with standardized uptake values less than 2. In contrast, images from uninfected, loose hip prostheses revealed very intense uptake around the head or neck of the prosthesis with standardized uptake values as high as 7. It is concluded that the intensity of increased FDG uptake is less important than the location of increased FDG uptake when FDG PET is used to diagnose periprosthetic infection in patients with hip arthroplasty. Using increased uptake as the sole criterion for diagnosing infection will result in false positive results in this setting.

[Clinical significance of Q-Tc dispersion after exercise in aged patients with old myocardial infarction]

OBJECTIVE

This study was aimed to evaluate clinical significance of Q-Tc dispersion after exercise in aged patients with old myocardial infarction.

METHOD

Sixty-four aged patients with old myocardial infarction(infarction group) were examined by treadmill exercise, dynamic electrocardiography, echocardiography, and were followed up for average of 24.12 +/- 7.7 months. 30 healthy aged persons were served as control group.

RESULTS

Compared with that (40.21 +/- 15.21 ms) before exercise, Q-Tc dispersion (59.37 +/- 20.17 ms) was increased significantly after exercise in infarction group(P < 0.01). But no significant difference was found in Q-Tc dispersion of control group before and after exercise(34.70 +/- 12.29 ms vs 38.91 +/- 13.62 ms P > 0.05). In infarction group, occurrence of abnormal contraction of left ventricular wall, aneurysms, NYHA III class and > III class of Lown's ventricular arrhythmia classification was significantly higher in Q-Tcd > 50 ms patients than that in Q-Tcd < 50 ms ones(P < 0.05). It was found that 5 patients died of cardiac sudden death in Q-Tcd > 50 ms patients and no one died of cardiac sudden death in Q-Tcd < 50 ms ones.

CONCLUSION

The Q-Tc dispersion after exercise is an important index to predict ventricular arrhythmia and cardiac death in the patients with old myocardial infarction.

[Does semi-quantitative analysis of FDG-PET have any additional value in the diagnosis of mesial temporal sclerosis?]

The aim of this study was to compare qualitative visual analysis with semi-quantitative analysis in the diagnosis of mesial temporal sclerosis (MTS) using FDG-PET.

METHODS

This study included 21 patients with histopathological confirmation of MTS. FDG-PET visual analysis data were based on clinical reports generated soon after the completion of the scan. FDG-PET images were semi-quantitatively analyzed using regions of interest (ROIs) in 19 slices perpendicular to the longest axis of the temporal lobe. These ROIs divided each temporal lobe into three regions (lateral, inferior and medial). An asymmetry index was calculated for each region.

RESULTS

The visual analysis of the FDG-PET studies demonstrated asymmetric hypometabolism in all patients. All but 1 patient underwent standard lobectomy of the same side described as hypometabolic by the PET report. Using an asymmetry index equal or greater than 9% in at least one of the regions as a threshold, the FDG-PET semi-quantitative analysis showed significant asymmetry in 18 patients. These also matched the side of lobectomy and were confirmed as sclerotic in all but one patient (same patient as above).

CONCLUSION

The semi-quantitative analysis did not provide additional information over visual interpretation in this series of patients.

Relationships involving metastable equilibrium solubility, surface complexes, and crystallite disorder with carbonated apatites

Previous studies have shown that the metastable equilibrium solubility (MES) behavior of carbonated apatites (CAPs) may be described by a surface complex with the hydroxyapatite (HAP) stoichiometry in the absence of solution fluoride and by that with the fluorapatite (FAP) stoichiometry when appreciable solution fluoride is present. Studies have also shown that the magnitude of the MES is directly related to the crystallinity of the CAP. The aim of the present investigation was to examine the relationship between the CAP MES determined in the presence of solution fluoride and CAP crystallinity and to examine the effect of the change in the stoichiometry of the surface complex (from that of HAP to that of FAP) upon the relationship of the CAP MES to crystallinity. CAP samples were prepared by methods based on the precipitation of CAP from calcium phosphate solutions and the hydrolysis of dicalcium phosphate dihydrate in bicarbonate solutions. From X-ray diffraction experiments, the crystallite microstrain, and the full width at half maximum (FWHM) of the 002 reflection were determined for the CAPs. From CAP MES experiments conducted in the presence of solu tion fluoride, linear plots of the mean MES (i.e., mean pK(FAP)) values vs the crystallinity parameter (i.e., microstrain and FWHM) were obtained that yielded slopes that were essentially the same as those obtained in the absence of solution fluoride (i.e., mean pK(HAP) values vs crystallinity). This parallel finding suggests that the CAP crystallite disorder affects the energetics of the two surface complexes essentially to the same extent and provides new insight into the nature of CAP surface complexes.

[Development of a diagnostic kit of enzyme-linked immunoassay for detecting serum anti-hepatitis E virus IgG]

OBJECTIVE

To develop a diagnostic kit for detecting serum anti-hepatitis E virus (HEV) IgG with enzyme-linked immunoassay (ELISA).

METHODS

The diagnostic kit of detecting anti-HEV IgG with ELISA was prepared by two synthetic HEV peptides used for coating the solid-phase to capture the antibody against HEV in serum, and then by horseradish peroxidase antihuman IgG (gamma chain) added as the second antibody to bind the anti-HEV IgG in serum. Its sensitivity, specificity, precision and stability were measured and clinically evaluated.

RESULTS

The sensitivity, specificity, and precision of the diagnostic kit detected by the China National Institute for the Control of Pharmaceutical and Biological Products were 90% (1/10), 100% (0/30) and < 15%, respectively, meeting the national standards for detecting serum anti-HEV IgG with ELISA. The ELISA Kit is stable for 1 year at least under 4 degrees C. The total consistency rates were 100% (43/43) and 96.6% (86/89), as compared with Genelabs and Singaporean DBL kits. This diagnostic kit for detecting serum anti-HEV IgG with ELISA was evaluated and approved by the State Drug Administration, China and a certificate was conferred in 1998.

CONCLUSIONS

The diagnostic kit for detecting anti-HEV IgG with ELISA can be used for epidemiological studies and clinical diagnosis of HEV infection.

Dual time point 18F-FDG PET imaging for differentiating malignant from inflammatory processes

The aim of this study was to investigate the difference in the rates of FDG uptake between malignant and inflammatory cells and processes.

METHODS

IN VITRO STUDIES

(18)F-FDG uptake by different tumor cell lines (human mesothelioma [REN]; rat mesothelioma [II45]; mice melanoma [B18F10]; mice mesothelioma [AB12]; human myeloma [GM1500]; and human ovarian cancer [SKOV3]) and peripheral blood mononuclear cells isolated from 8 healthy human volunteers was measured 20 and 60 min after FDG was added into growth medium. Animal studies: II45 cells were implanted into the left flank of rats (n = 5) and a focal inflammatory reaction (mechanical irritation) was generated in the right flank. PET images at 45 and 90 min after injection of FDG were obtained and standardized uptake values (SUVs) were determined. Patient studies: Seventy-six patients who had dual time FDG PET scans were retrospectively analyzed. All results were expressed as the percentage change in SUV of the later time image from that of the earlier time (mean +/- SD).

RESULTS

IN VITRO STUDIES

Except for the SKOV3 cell line, which had only minimally increased FDG uptake (+10% +/- 26%; P > 0.3), all other tumor cell lines tested showed significantly increased FDG uptake over time (GM1500, +59% +/- 19%; B18F10, +81% +/- 15%; AB12, 93% +/- 21%; II45, +161% +/- 21%; REN, +198% +/- 48%; P < 0.01 for all). By contrast, FDG uptake in mononuclear cells was decreased in 7 of 8 donors. Animal studies: SUVs of tumors from 90-min images were significantly higher than those from 45-min images (+18% +/- 8%; P < 0.01), whereas the SUVs of inflammatory lesions decreased over time (-17% +/- 13% of the early images; P < 0.05).

CLINICAL STUDIES

The SUVs of delayed images from the known malignant lesions compared with those of earlier scans increased over time (+19.18% +/- 9.58%; n = 31; P < 0.001; 95% confidence interval, 15.8%-22.6%). By contrast, the SUVs of benign lung nodules decreased slightly over time (-6.3% +/- 8.1%; n = 12; P < 0.05; 95% confidence interval, -10.9% to -1.7%). The SUV of inflammatory lesions caused by radiation therapy (+1.16% +/- 7.23%; n = 8; P > 0.05; 95% confidence interval, -3.9%-6.2%) and the lesions of painful lower limb prostheses (+4.03% +/- 11.32%; n = 25; P > 0.05; 95% confidence interval, -0.4%-8.5%) remained stable over time.

CONCLUSION

These preliminary data show that dual time imaging appears to be useful in distinguishing malignant from benign lesions. Further research is necessary to confirm these results.

An extended self-organizing map network for modeling and control of pulse jet fabric filters

Pulse jet fabric filters (PJFFs) have become an attractive option of particulate collection utilities, because they can meet stringent particulate emission limits regardless of variation in operating conditions. Despite their wide applications, the present control algorithm for PJFFs can best be described as rudimentary. In this paper, a modeling and control strategy based on the local model network (LMN) is proposed. An extended self-organizing map (ESOM) network is developed to construct the LMN model of the filtration process using the filter's input-output data. Subsequently, these ESOM local models are incorporated into the design of local generalized predictive controllers (GPC), and the proposed controller design is obtained as the weighted sum of these local controllers. Simulation results show that the proposed controller design yields a better performance than both conventional GPC and proportional plus integral (PI) controllers yield.